"Distance will die,” or so predicted British economist Frances Cairncross, along with a host of social and media theorists, following the spread of the internet in the 1990s. At the dawn of this digital transformation, many theorists thought that, since the Internet allows us to work and connect with each other from anywhere, we would no longer need physical space. It could be the end of the city as we knew it.

Reality proved them wrong. We know that cities in the last 20 years have been experiencing unprecedented growth: by 2050 the UN predicts that two thirds of the world’s population will live in urban areas. So, the Internet has not killed cities – but neither has it left them unaffected.

In fact, in parallel to sustained demographic and economic growth, cities have started to incorporate digital networks into the previously un-sensing physical space. Millions of sensors - in streets, in cars, in buildings, even in every person’s pocket, with today’s ubiquitous smartphones - have ushered in a great technological upheaval.

In the urban context, such upheaval is often called the “smart city.” Essentially, smart cities are nothing more than the outcome of broad technological trends that have been unfolding over the last two decades. The Internet is entering physical space, becoming the Internet-of-Things (IoT) – and ushering in a series of unprecedented possibilities in terms of how we can understand, design and live. However, I should say that I do not like the term “smart” city: I prefer the terms “Senseable City”, as in the name of our lab at MIT. The “senseable” neologism that means both “able to sense” and “sensible,” emphasizing the human – as opposed to merely technological – side of things.

The applications that such technologies can have on cities are manifold, cutting across all sectors – from citizen participation to planning, from mobility to energy, from water to waste. As cities find themselves at the heart of more and more challenges, technology can help us envision innovative urban solutions to be scaled up across the world.

Many of these solutions leverage on one of the new building blocks of the digital era: the data that is gathered in staggering quantity in cities. Data gives us better knowledge of the urban environment, and thus its potential beneficial applications are countless. For example, data can be used to empower citizens to be more active in their cities by supplying them with previously inaccessible information on their surroundings.

This is something we looked into at the Senseable City Lab at MIT. Our Trash Track project had Seattle residents put geo-localizable tags on pieces of their trash, so we could follow them through the U.S. waste disposal system. One of the most significant results of the study was the behavioral change these discoveries prompted in the residents. Unveiling the routes that objects takes after being discarded provides better insights into the consequences of our consumption patterns – a first step to change them.

The ability to process data is also essential to numerous projects of the Senseable City, like, notably, mobility. In the last decades, digital technologies have gradually been transforming cars into computers on wheels, equipped with many thousand sensors per vehicle. This evolution is at root of the next great revolution in transportation, “driverless mobility”, whose consequences might be to be as profound on life in our cities as the appearance of the first “horseless carriages” in the late 19th century.

Over the last few years, our lab has investigated how a world of driverless cars might impact urban infrastructure. In fact, more than just allowing us to shamelessly nap or text at the wheel, self-driving or autonomous vehicles (AVs) are poised to blur the historical distinction between public and private transportation, as they could be used constantly throughout the day by many different people and not sit idle for 95% of the time, as it is estimated for today’s private cars.

In this sense, AVs would be likely to intensify a trend that, albeit in a different form, is evident in more and more cities internationally: that is, sharing. Digital services such as Car2Go and ZipCar are already having as a consequence a reduction in the total number of cars in circulation. With the combinate effects of self-driving cars and sharing, it has been estimated that dense cities could potentially satisfy the mobility demand with just a fraction of the current number of vehicles.

Such a scenario could have major consequences. Large parking lots could be rendered useless and should be converted to more sustainable uses: an exciting challenge for city officials and designers alike. The improvements in term of environmental conditions might even be felt at a global scale, as in most cities, more than 25% of all energy consumption is linked with transport.

AVs and ride sharing could create overwhelmingly positive changes in urban transportation. But if the transition to the driverless city is not managed carefully, it could also lead to negative consequences. The first concern is safety. We all know what it is like for a virus to crash a computer. What if a virus crashes a car? Malicious hacking is difficult to combat with traditional government and industry tools, and it is particularly dangerous in the case of systems, such as self-driving cars, that combine the digital and the physical.

Additional problems might arise from what one could call the “unfair competitive advantage” of vehicle autonomy. The cost of traveling a mile might drop so substantially that people would abandon public transportation in favor of autonomous cars. That, in turn, could lead to an increase in the number of vehicles in a city—and with that in- crease, surreal gridlock. Additionally, keeping cars moving at all hours rather than parked 95 percent of the time could increase pollution.

Autonomous cars might generate another unintended consequence: aggravating urban sprawl. In the future, what if people, newly able to commute while sleeping or working, decide to relocate out of the city, consuming land and expanding unsustainable, sprawling communities? As Robin Chase wrote, “Simply eliminating the drivers from cars, and keeping everything else about our system the same, will be a disaster.”

In conclusion, although digital technologies did not kill distance or the city, they still changed the latter fundamentally. The city is transforming from an exclusively physical space to one at the intersection of the physical and the digital. However, it is imperative that we view these new technologies with a critical eye—and guide them toward the societal goals we desire. Good policy could help prevent the negative outcomes we have described. As it the case in many innovation ecosystems, much will depend on a healthy cycle of trial and error. Such should be one of the key aims of a “Senseable City”.